Grease interceptor



Nov. 9, 1948.

INVENTOR. STANLEY J-GRUM.

dMw.

s. 'GRUM GREASE INTERCEPTOR Filed July 19, 1945 Patented Nov. 9, 1948GREASE INTERCEPTOR Stanley J. Grum, Michigan City, Ind., assignor toJosam Manufacturing Company, Cleveland, Ohio, a corporation of DelawareApplication July 19, 1945, Serial No. 605,945

The present invention relates to an improved grease interceptor of thetype comprising a closed top intercepting chamber into which waste wateris directed for causing separation of grease and other light weightWaste materials from the Water in the chamber, the clarified water beingdischarged from the chamber through a passage leading from the bottom ofthe chamber upwardly to a sewer connection located at the normal waterlevel in the chamber.

Heretofore, it has been a practice to provide an air relief passagebetween the area over the waterin the chamber and the outlet passage ofthe chamber, which relief passage had its inlet at the top of thechamber and its outlet in the chamber outlet passage slightly below thenormal static water level of the chamber. This arrangement enabled airto escape from the area above the Water level when the Water level wasraised by incoming waste water. By locating the outlet of the airpassage below the water level in the interceptor outlet, an effectiveseal or trap was provided for preventing sewer gases from entering theintercepting chamber through the air relief passage.

This'arrangement was not satisfactory, however, because there wasconsiderable resistance to the escape of air through the relief passagedue to friction in the passage and, principally because the water headover the outlet of the relief passage would increase considerably duringsurges of waste water into the interceptor. The result was thatpneumatic pressure developed above the liquid in the chamber and thispressure depressed the water level below the normal static level andcaused a surge of water to discharge from the interceptor, therebylowering the static water level below that for which the interceptor wasdesigned. This reduction in the normal static level decreased thecapacity and efficiency of the interceptor.

An object of the present invention is to provide a grease interceptor ofthe type described in which the air relief passage has its outlet in thelow pressure area of the vena contracta of the water stream formed inthe outlet passage of the interceptor and below the liquid level in thelatter outlet.

Reduction in back pressure to air release is also efiected by shapingthe trap outlet easement to the sewer so that friction to water flow isreduced to a minimum, thereby requiring less lead to induce flow. Thus,the increase in pressure over the liquid will be minimized during surgesof waste Water into the interceptor by the relief of 1 Claim. (01.182-9) air from the interceptor and by the ready fiow of the liquid fromthe interceptor.

Other objects and advantages of the invention will be apparent from thefollowing description of a preferred form of embodiment of theinvention, reference being had to the accompanying drawing wherein:

Fig. 1 is a view in section of a grease interceptor embodying myinvention; and 1 Fig. 2 is a fragmentary view in section, the sectionbeing taken on line 22 of Fig. 1.

Referring to the drawings, I have shown a grease interceptor indicatedgenerally at 5, which interceptor is adapted to be connected in thedrain of a sink or the like, from which water, laden with grease andother light weight waste material, is discharged. The interceptorremoves light Weight Waste materials from the waste Water and dischargesthe clarified Water into a sewage system, for example. Although theinvention may be embodied in different forms of interceptors, for thepurposes of illustrating the invention, the interceptor 5 comprises acubical intercepting chamber 6, which may be formed of iron or steel,and having an inlet connection 1 formed in the end wall 8 for connectingthe cham-- ber with the drain pipe of a sink, or other source of greaseladen water. The outlet of the chamber 6 is formed at the end oppositethe inlet, and comprises a pocket or offset 9 communicating with thechamber through an opening ID at the bottom of the end wall I l. Avertically extending tube l2 leads from the pocket 9 upwardly to ahorizontally extending sewer connection I l. The pocket 9 and the tubel2 form a trap leg through which water from the lower portion of thechamber 6 may be discharged into a sewer system. The static water levelin the chamber is indicated by the line A, and this level obtains duringthe time no water is discharged into the interceptor. During flow ofwater into the chamber 6, the level will be above the static level.

Means is provided in the conduit l2 for forming an orifice effect sothat a low pressure area is created in the conduit by the flow of watertherethrough, the purpose of which will appear hereinafter. Preferably,this means comprises a ring-like flange structure l5 which projectsinwardly from the walls of the conduit I2 for forming a restrictedopening l9 through which the discharge water passes. This structure 15is located slightly below the opening outlet of the connection l4 sothat it lies below the static liquid level in the interceptor.

In the interceptor shown, the action of the water in the chamber iscontrolled by two sets of cascades I6, only one set appearing in thedrawings, formed in the bottom wall of the chamber and separated by achannel I1, and baffles [8 extending transversely of the chamber. Thisconstruction facilitates the separation of the light weight materials,from the Waste water, but other suitable arrangements may be utilizedfor'this purpose.

The top of the chamber 6 is adapted to be closed by a removable coverplate 20 which is secured over the chamber by a turned over edgef2l-engaging a flange 22 extending along the upp redge of wall 6, and awing nut '25 lthreadedon albolt 24 extending from the chamber walls andthrough an opening in the cover plate. Preferably, a gasket 25 isinterposed between thecover plate 20 and the upper edges of the chamberwalls for forming an air-tight seal between the Walls and .the coverplate.

'To relieve the air from the area above the water level in the chamber 5during theinflow of waste water, I have provided an air relief passageextending between the top portion of the chamber and the outlet tube 12.The outlet 30 ofthe air relief passage islocatedlin the wall H .at thetop of the chamber 20 so that it will always be above the normal waterlevels in the chamber. From the inlet 30 the air passageis formed by adownwardly extending conduit 3|, which conduit has an outlet 32 openinginto conduit l.2 immediately above the neck-like structure l5. It willbe apparent that as the clarified water flows through tube 12 .to thesewer connection M, a vena contracta eifect will be created at thstructure [5 and a low pressure area will exist at the outlet 32 of theairrelief passage, Thus, movement of air through the relief passage willbe induced by the flow of water through tube I2 and there will be nopressure over the liquid in the chamber to cause surging and lowering ofthe liquid level in the chamber. Furthermore, since the outlet 32 of theair relief passage is below the static water :level, the passage issealed against the entrance of sewergases.

able pressures above the liquid in the chamber and at the same time, aneffective seal is provided against the entrance of sewer gas into theair relief passage and intercepting chamber. By my invention; surging ofthe liquid in the interceptor is .obviated and full eihciency of theinterceptor is maintained.

Although I havedescribed but one form of the invention, other formsmight be adopted, all falling within the scope of the claim whichfollows.

I claim:

In a grease interceptor, a closed chamber adapted to receivegrease-ladened water said chamber having an outlet comprising a conduit,

circular in cross section, leading from adjacent the bottom of thechamber to an opening .dis- 'posed below the top of the chamberwhereby'a body of liquid is maintained inthe chamber; .a

ring like formation projecting inwardly from the walls of the conduitbelow said opening an'd'iorming a constriction in said conduit; andmeans forming an air relief passage interconnecting said chamberandconduit, said passage"havingfits'inlet disposed in said chamber abovethe liquidlevel therein and its outlet disposed immediately above saidring like member iandbelow said opening.

STANLEY J. GRUM.

REFERENCES crimp The following references are of -recordin the "file ofthis patent:

UNITED 'STA'I'ES PATENTS .Number Name Date 2,268,854 Boosey Jan 6, 19422,272,912 Heinkel .Feb. 10,1942 2,284,737 Hirshstein June -2, 19422,345,787 Boosey .Apr. 4,, 1944:

